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PROJECT REPORT
ON
CHARACTERISTIC VERIFICATION AND GAIN LINEARIZATION OF N.T.C. THERMISTOR
PRESENTED BY
Ms. P. VEENASHEELA RAO
AM – 097234-5
UNDER THE ESTEEMED GUIDANCE OF
Prof. (Dr.) S. B. LAL SEKSENA
DEPARTEMENT OF ELECTRICAL ENGG.
N . T . C . T H E R M I S T O R
NIT, JAMSHEDPUR
CERTIFICATE
This is to certify that Ms. P. Veenasheela Rao (AM-097234-5) of PG Diploma in Electronics and Communication Engineering with specialization in “Instrumentation and Control Engineering” has completed the project work entitled “CHARACTERISTIC VERIFICATION AND GAIN LINEARIZATION OF N.T.C. THERMISTOR” which is a bona-fide record of the work, is carried out independently and systematically by her under my guidance and supervision.
This project work has been carried out in partial fulfillment of the requirement for Part-IIB of the Postgraduate Diploma Examination of “THE INSTITUTION OF ENGINEERS (INDIA)” and has been implemented successfully as per the guidelines laid down by “THE INSTITUTION OF ENGINEERS (INDIA)”.
It is further certified that this report or the part of its contents have not been submitted to any other Institution or University for the award of any Certificate, Diploma or Degree.
SIGNATURE: Project Guide: Prof. (Dr.) S. B. LAL SEKSENA
DATE: F.I.E. ( I ) : 106427 / 4ELDepartment Of Electrical Engineering,N.I.T. Jamshedpur
CERTIFICATE OF ORIGINALITY
I, Ms. P.Veenasheela Rao, (AM-097234-5) of PG Diploma in Electronics and Communication Engineering with specialization in Instrumentation and Control Engineering of “The Institution of Engineers (India)”, do hereby state that the project work entitled “Characteristic Verification And Gain Linearization of NTC Thermistor” is an original work and has not been submitted earlier to any other Institution or University for fulfillment of the requirement of any course of study.
SIGNATURE:
DATE: Ms. P.Veenasheela Rao
PLACE: AM-097234-5
ACKNOWLEDGEMENT
I would like to take this golden opportunity to express my sincere gratitude to my project guide Prof. (Dr.) S. B.LAL SEKSENA for providing me valuable guidance and inputs which helped me to complete this project in true sense.
I wish to express my sincere thanks to Mr. Shatrughan Singh, H.O.D., Deptt. of Electronics and Comm. Engg., Al-Kabir Polytechnic, Jamshedpur, for his consent to carry out my project work in the department. I am thankful to Mr. Prem Kumar Sharma, Lab Technician in Electronics & Comm. Engg. Deptt. , Al-Kabir Polytechnic, for assisting me to complete this project. I express my thanks to my colleagues for their support & full co- operation.
I am thankful to Mr. Mohammad Yasin (HOD) and Mr. Syed Aatif Gulrez of Computer Science & Engg. Deptt., Al-Kabir Polytechnic; for their full co-operation in the preparation of Project-Report.
Last but not the least, I express my thanks to my husband and children for their inspiring & motivating attitude. It is the result of their sincere co-operation that I finished my project in stipulated time.
Ms. P. Veenasheela Rao
Submitted by: -
Ms. P. VEENASHEELA RAO
AM-097234-5
SYNOPSIS
TITLE OF THE PROJECT
GAIN LINEARIZATION OF N.T.C.THERMISTOR.
OBJECTIVE OF THE STUDY
TO LINEARIZE THE N.T.C.THERMISTOR RESPONSE CURVE USING “HARDWARE LINEARIZATION SOLUTIONS”.
RATIONALE OF THE STUDY
TO UNDERSATND THE CHARACTERISTIC CURVE OF N.T.C. THERMISTOR.
The change in the resistance of a N.T.C. Thermistor with increasing temperature is remarkably non-linear. If a nearly linear resistance curve is required while measuring a wide range of temperature, a resistor connected in series or in parallel provides an approximation of linearity however the temperature range exceeds 50 to100Kelvin.
LITERATURE REVIEW
Copious work has been done by fellow researchers on GAIN LINEARIZATION OF N.T.C. THERMISTOR since its inception. As because the thermistor is a potential candidate for measuring temperature due to its small size (tailor mode) and it has many advantages. So, I have selected NTC thermistor for my project work.
DETAILED METHODOLOGY TO CARRYOUT THE STUDY
STUDY THE CHARACTERISTIC CURVE IN RESISTANCE-VS-TEMPERATURE MODE. STUDY THE GRAPH OF VOLTAGE ACROSS THERMISTOR-VS-TEMPERATURE IN ZERO-POWER
CONDITION. STUDY THE GRAPH OF OUTPUT VOLTAGE-VS-TEMPERATURE. STUDY THE “HARDWARE LINEARIZATION SOLUTIONS”. ANALYZE THE CHARACTERISTIC CURVE IN RESISTANCE-VERSUS-TEMPERATURE MODE WITH
THE LINEARIZATION CIRCUITRY. ANALYZE THE GRAPH OF OUTPUT VOLTAGE-VERSUS-TEMPERATURE WITH THE
LINEARIZATION CIRCUITRY.
EXPECTED CONTRIBUTION
REDUCE THE NON-LINEARITY IN THE CHARACTERISTIC CURVE OF N.T.C. THERMISTOR. UTILIZE THE “HARDWARE LINEARIZATION SOLUTIONS”.
LIST OF ACTIVITIES
DISCUSSION WITH PROJECT GUIDE. SELECTION OF PROJECT TOPIC WITH THE HELP OF PROJECT GUIDE. STUDY AND ANALYSIS OF DETAILED METHODOLOGY OF THE PROJECT. ANALYSIS OF DESIGNING OF “HARDWARE LINEARIZATION SOLUTIONS” AND CONSULTATION
WITH THE PROJECT GUIDE. BRAINSTORMING ON THE HARDWARE LINEARIZATION SOLUTIONS. SELECTION OF THE HARDWARE LINEARIZATION SOLUTIONS. IMPLEMENTATION OF THE HARDWARE LINEARIZATION SOLUTIONS. PREPARATION OF THE PROJECT REPORT. FINAL PRESENTATION.
0 2 4 6 8 10 12
NUMBER OF WEEKS
Discussion With Project Guide
Selection of project topic.
Study and analysis of detailed methodology.
Designing of “hardware linearization solutions”.
Brainstorming.
Preparation of Project Report.
Implementation.
Final presentation.
LIST OF ACTIVITIES
GANTT CHART SHOWING PROJECT ACTIVITIES WITH TIME FRAME
LAB & PLACE
ANALOG ELECTRONICS LAB, ELECTRONICS & COMM. DEPTT.AL-KABIR POLYTECHNIC, JAMSHEDPUR.
INSTRUMENTS USED
1) DISCRETE COMPONENT TRAINER (OMEGA TYPE ETB-84)2) DIGITAL MULTIMETER3) DIGITAL THERMOMETER4) ELECTRIC HEATER5) REFRIGERATOR6) DESKTOP COMPUTER
PROBLEM FACED
1) HIGHER COLD RESISTANCE VALUE THERMISTOR IS NOT EASILY AVAILABLE IN JAMSHEDPUR.2) DESIGNING OF CONSTANT-CURRENT-SOURCE OF VERY SMALL CURRENT i.e. 20µA IS
CUMBERSOME.3) TO OBTAIN NEGATIVE TEMPERATURE FOR EXAMINING NON-LINEARITY OF THERMISTOR IS
ALSO DIFFICULT.
PRESENTED BY:
SIGNATURE:
NAME: Ms. P. VEENASHEELA RAO
AM-097234-5
LECTURER, ELECTRONICS & COMM. ENGG. DEPTT.
AL-KABIR POLYTECHNIC, JAMSHEDPUR.
APPROVED BY:
SIGNATURE:
PROJECT GUIDE: Prof. (Dr.) S. B. LAL SEKSENA
F.I.E. ( I ) : 106427 / 4EL
DEPARTMENT OF ELECTRICAL ENGINEERING,
N.I.T. JAMSHEDPUR-831014s
CONTENTS
Topic Page
1. Literature Review --------------------------------2. Introduction ----------------------------------------3. Parameters of Thermistor ---------------------4. N.T.C. Thermistor Characteristic ------------5. Gain Linearization of N.T.C. Thermistor ---6. Steinhart-Hart Equation ------------------------7. Advantages ---------------------------------------8. Applications ---------------------------------------9. Comparison of Temperature Sensors -------10. Experimental Details for 47Ω, 100 Ω and 10k Ω Thermistors
10.1- Electrical Configuration for Thermistor ----10.2- Constant-Current-Source ---------------------10.3- Data Specifications -----------------------------10.4- Tables of Experimental Observations -----10.5- Graphs --------------------------------------------
11. Observation ---------------------------------------12. Conclusion ---------------------------------------- 13. References ---------------------------------------
1. Literature Review
Thermistors (a contraction of thermal resistor) are semiconductors which behave as resistors with a high negative temperature coefficient of resistance.
Manganese, nickel or cobalt oxides are milled, mixed in proper proportion with binders, pressed into desired shapes and then sintered to form thermistors in the form of beads, rods or discs. Sometimes a glass envelope is provided to protect a thermistor from contaminants.
The resistance RT of a thermistor at temperature T can be written as
RT = R0 exp [β (1/T – 1/T0)] ---------- (1)
This equation can be rearranged to the form
1/T = (1/T0 – 1/ β ln R0 ) + 1/ β ln RT ---------- (2)
= A + B ln RT
Where A and B are constants. Equation (2) may alternatively be used to find temperatures by evaluating A and B from two pairs of known values of RT and T.
Thermistors are very popular as temperature transducers because1. their calibration is stable,2. they are compact, rugged, inexpensive,3. they have a small response time,4. they are amenable to remote measurements and above all,5. their accuracy is rather high.
2. Introduction
The term “thermistor” originated from the descriptor THER Mally Sensitive ResISTOR. The two basic types of thermistors are the Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC). The NTC thermistor is best suited for precision temperature measurement. The PTC is best suited for switching applications. The NTC thermistor is used in three different modes of operation which services a variety of applications. One of the modes exploits the resistance-versus-temperature characteristics of the thermistor. The other two modes take advantage of voltage-versus-current and current-over-time characteristics of the thermistor.
NTC Thermistors are ceramic semi-conductor elements made from metal oxides which have a predictable and repeatable R-T curve. The resistance changes are non-linear and exhibit a Negative Temperature Coefficient therefore their resistance, at a determined measuring power, declines as the temperature of the device increases and vice versa. NTC thermistors can be used when temperature compensation, temperature measurement or control, or inrush surge current protection are needed.
2.1 Self Heating
A thermistor is a resistor, and, just like any resistor, it produces heat energy whenever current passes through it. The heat energy causes the NTC thermistor's resistance to reduce which then indicates a temperature slightly above ambient temperature. In the manufacturer's data sheets and application notes, there are usually tables, formulae, and text detailing this phenomenon. However, these may be largely ignored if the current through the thermistor is kept relatively low such that self heating error is small compared to the required measurement accuracy.
2.2 Zero-Power Sensing
When utilizing a thermistor for temperature measurement, control and compensation applications, it is very important not to “self-heat” the thermistor. Power, in the form of heat, is produced when current is passed through the thermistor.Since a thermistor’s resistance changes when temperature changes, this “self generated heat” will change the resistance of the thermistor, producing an erroneous reading.
The power-dissipation constant is the amount of power required to raise a thermistor’s body temperature 1C. a standard chip thermistor has a power constant of approximately 2 mW/C in still air. In order to keep the “self heat” error below 0.1C power dissipation must be below 0.2 mW. Very low current levels are required to obtain such a low power dissipation factor. This mode of operation is called “zero-power” sensing.
3. Parameters of Thermistor
3.1 Zero-Power Resistance Rt
The resistance value measured at the rated temperature using a power level which causes a resistance change that can be ignored relative to the measurement error as a whole. Since the resistance values are high and the change in R values are generally great, the errors created by measurement and long lead wires can be ignored.
3.2 Rated Zero Power Resistance R25
The rated resistance of thermistor which is the zero power resistance measured at 25°C and indicated on the thermistor. This is the most common value used to describe the resistance value of a thermistor.
3.3 Beta Value
β or beta value is an indication of the slope of the curve which represents the relationship between the resistance and the temperature of a particular thermistor measured under zero power conditions. The higher the Beta value the greater the change in resistance per degree C.
It can be calculated the RT2 using this formula:
Here: β =3380, T1=25, RT1 =10kohmRT1 - The zero power resistance at T1
RT2 - The zero power resistance at T2
Unless otherwise indicated, the B value is calculated using the zero power resistance at 25 deg. C (298.15K) and at 50 deg. C (323.15K). The Beta value is not a rigorous
constant and is temperature dependant within a small range of operating temperatures.
3.4 Temperature Coefficient of Zero-Power Resistance-αT
The temperature coefficient or alpha (symbol) at a specified temperature is the average percent change of the zero power resistance per degree C to the rated resistance (R25).Namely:
Where: α T - The temperature coefficient of the zero power resistance at TRT - The zero power resistance at TT - TemperatureB - B value
3.5 Dissipation Coefficient δThe dissipation coefficient is the ratio of the rate of change of the power consumption of a thermistor to the change of it’s corresponding temperature, namely:
The value of δ will change for different ambient temperatures and transfer mediums and should be used for reference purposes only.
The dissipation constant of a thermistor is the amount of power expressed in (mW/°C) required to self-heat it by 1°C above ambient temperature.
3.6 Thermal time constant τ The thermal time constant is the time in seconds needed for a thermistor to register a change of 63.2% of the difference between the initial temperature of the thermistor
and that of its surroundings when subjected to a stepped change in temperature under zero power conditions.τ is in direct ratio to the thermal capacity (C) of the thermistor and in inverse ratio to the dissipation coefficient namely:
3.7 Max. Steady State Current
The maximum allowable continuous current allowed to pass through the thermistor at 25 deg. C.
4. NTC Thermistor CharacteristicAs the name implies, the thermistor is just a temperature-dependent resistor. Unfortunately, the dependence is very non-linear (Figure 1) and, by itself, would not be very helpful for most applications.
Figure 1. NTC thermistor resistance varies extremely non-linearly with temperature. This makes it difficult to utilize the thermistor without applying it in a linearizing network. (R25C = 10kΩ, β = 3965K).
The standard formula for NTC thermistor resistance as a function of temperature is given by:
where R25C is the thermistor's nominal resistance at room temperature, β (beta) is the thermistor's material constant in K, and T is the thermistor's actual temperature in Celsius.
This equation is a very close approximation of the actual temperature characteristic, as can be seen in Figure 2. Log-scale is used for the Y-axis.
Figure 2. Thermistor resistance versus temperature is almost linear on a semi-log graph. The actual measured thermistor resistance matches the Beta formula to a fairly high degree of precision. (R25C = 10kΩ, β = 3965K).
R25C and β are usually published in the manufacturer's data sheet. Typical values of R25C range from 22Ω to 500kΩ. Typical values of β are from 2500 to 5000K.
As seen in Figure 3, higher values of β provide increased temperature dependence and are useful when higher resolution is required over a narrower temperature range. Conversely, slower values of β offer less-sloped temperature dependence and are more desirable when operating over a wider temperature range
Figure 3. An NTC thermistor is specified by its room temperature resistance (R25C) and its material constant β (Beta). Beta is a measure of the slope of temperature dependence. (R25C = 10kΩ, β in K).
5. Gain Linearization of NTC Thermistor
Linearizing
An NTC thermistor is most easily utilized when applied in a linearizing circuit. There are two simple techniques for linearization: resistance mode and voltage mode.
5.1 Resistance Mode
In resistance mode linearization, a normal resistor is placed in parallel with the NTC thermistor, which has the effect of linearizing the combined circuit's resistance. If the resistor's value is chosen to be equal to the thermistor's resistance at room temperature (R25C), then the region of relatively linear resistance will be symmetrical around room temperature (as seen in Figure 4).
Figure 4. Resistance mode linearization is easily accomplished by placing a normal resistor in parallel with the thermistor. If the normal resistor has the same value as R25C, then the region of nearly linear resistance versus temperature will be symmetrical around +25°C. (R25C = 10kΩ, β in K).It is noted that lower values of β produce linear results over a wider temperature range, while higher values of β produce increased sensitivity over a narrower temperature range. The equivalent resistance varies from roughly 90% of R25C at cold (-20°C) to 50% of R25C at room temperature (+25°C) to roughly 15% of R25C at hot (+70°C).
5.2 Voltage Mode
In voltage mode linearization, the NTC thermistor is connected in series with a normal resistor to form a voltage-divider circuit. The divider circuit is biased with a regulated supply or a voltage reference, VREF. This has the effect of producing an output voltage that is linear over temperature. If the resistor's value is chosen to be equal to the thermistor's resistance at room temperature (R25C), then the region of linear voltage will be symmetrical around room temperature (as seen in Figure 5).
Figure 5. Voltage mode linearization is easily accomplished by placing a normal resistor in series with the thermistor and biasing the resulting resistive voltage divider with a constant-voltage source. If the normal resistor has the same value as R25C , then the region of nearly linear output voltage versus temperature will be symmetrical around +25°C. (R25C = 10kΩ, β in K).
We note that lower values of β produce linear results over a wider temperature range, while higher values of β produce increased sensitivity over a narrower temperature range. The output voltage varies from near zero volts at cold (-20°C) to VREF/2 at room (+25°C) to near VREF at hot (+70°C).
6. Steinhart-Hart Equation
Although the thermistor has considerably better linearity than the thermocouple linearity, the thermistor still requires linearization in most temperature sensing circuits. The non-linear response of the thermistor can be corrected in software with an empirical third-order polynomial or a look-up table. There are also easy hardware linearization techniques that can be applied prior to digitalization of the output of the thermistor. The third-order polynomial is also called the Steinhart-Hart thermistor equation. This equation is an approximation and can replace the exponential expression for a thermistor. Wide industry acceptance makes it the most useful equation for precise thermistor computation.
The Steinhart-Hart equation is:
T = 1/(A0 + A1 ( ln RT ) + A3 ( ln RT3 )
ln RT = BO + B1 / T + B3 / T3
Where,
T is the temperature of the thermistor in Kelvin.A0, A1, A3, B0, B1 AND B3 are contents provided by the thermistor manufacturer.RT is the thermistor resistance at temperature, T.
With a typical thermistor, this third-order linearization formula provides ± 0.1C accuracy over the full temperature range. This is usually better than the accuracy of individual elements from part to part.
7. Advantages
The NTC thermistor as a temperature sensor, compared with other sensors in temperature measurement and control applications has following advantages:
1) Reliable performance;
2) High precision, good tolerances and interchangeability;
3) Large temperature coefficient of resistances;
4) High accuracy;
5) Low cost, especially for middle-or-low temperature and control;
6) High dissipation coefficient; test current can be greater than of traditional sensors;
7) Simplified circuitry;
Although the temperature range of the thermistor is the little better than the diode or silicon-based temperature sensors (-55 C to +175 C), it is still limited to a practical range of -100 C to +175 C.
Sensor Series
FT Series ST SeriesGD002 Series
GR Series
Temperature SensorHome Appliances (Air Condition, Refrigerator, Microwave, Washer & Dryer Accessories, etc)Automobile Supplies
Chip NTC ThermistorMotherboardTemperature Control Fan
SMD Chip NTC ThermistorMobile CellBattery ChargerMotherboardLCD Module
Glass Coating type NTCBattery ChargerBatteryAutomotives
Glass Coating type NTCHome Appliances Temperature ControllerAutomotives
8. APPLICATIONS
The NTC thermistor provides a near optimum solution for temperature-dependent regulation. It is low-cost, readily available through a variety of suppliers (Murata, Panasonic, etc.), and available in small surface-mount packaging from 0402 size through 1206 size. Furthermore, with only a basic understanding, the NTC thermistor is straightforward to apply to the circuit.
Applications using the first mode, resistance-versus-temperature, NTC Thermistor configurations, are the most prevalent. These circuits perform precision temperature measurement, control and compensation. Unlike applications that are based on the voltage-versus- current and current-over-time characteristics of the thermistor, the resistance-versus-temperature circuits depend on the thermistor being operated in a “zero-power” condition. This condition implies that there is no self-heating of the thermistor as a consequence of current or voltage excitation.
NTC thermistors for temperature measurement are suitable for a large variety of applications:
1) in household electronics: in refrigerators and deep freezers, washing machines, electric cookers, hair-driers, etc.
2) in automotive electronics: for measuring the temperature of cooling waters or oil, for monitoring the temperature of exhaust gas, cylinder head or breaking system, for controlling the temperature in the passenger compartment, etc.
3) in heating and air conditioning: in heating cost distributors, for room temperature monitoring, in under floor heating and gas boilers, for determining exhaust gas or burner temperature, as outdoor temperature sensors, etc.
4) in industrial electronics: for temperature stabilization of laser diodes and photoelements, for temperature compensation in copper coils or reference point compensation in thermoelements, etc.
5) in telecommunications: for temperature measurement and compensation in mobile phones.
9. Temperature Sensors - Comparing Types
Comparing advantages and disadvantages of thermocouples, RTDs and thermistors temperature sensors
Attribute
Thermocouple RTD Thermistor
Cost Low High Low
Temperature RangeVery wide
-350oF+3200oF
Wide-400oF
+1200oF
Short to medium-100oF+500oF
Interchange ability Good Excellent Poor to fair
Long-term Stability Poor to fair Good Poor
Accuracy Medium High Medium
Repeatability Poor to fair Excellent Fair to good
Sensitivity (output) Low Medium Very high
Response Medium to fast Medium Medium to fast
Linearity Fair Good Poor
Self Heating No Very low to low High
Point (end) Sensitive Excellent Fair Good
Lead Effect High Medium Low
Size/Packaging Small to large Medium to Small to
small medium
10. Experimental For 47 Ω, 100 Ω & 1k Ω N.T.C.Thermistors
10.1 Electrical configuration for thermistor
Vref
Precision Current Source = 20µA
NTC thermistor
VOUT
CIRCUIT DIAGRAM -1
10.2 Constant-Current-Source
Since the thermistor is a resistive element, current excitation is required. The current can originate from a voltage or current reference. The performance of a thermistor is fairly repeatable as long as the power across the device does not exceed the power dissipation capability of the package. Once this condition is violated, the thermistor will self-heat and artificially decrease in resistance, giving a higher than actual temperature reading.
IC +
RC = 10 KΩ _ +Vcc = 6V
+
BC107 _ -VEE = 6V
1kΩ-RB VZ= 3.3V IE I≅ C
RE = 120KΩ
Circuit Diagram 2 - Circuit of Constant-Current-Source of 20 A
ICIE=20A VZ=3.3V RE=120kΩ RC=10Ω to 100 kΩRB=1kΩ +VCC = +6V -VEE = -6V
20µA +
_ +Vcc= +6V
mV
+
NTC _ -VEE = -6V
IC
BC107
RB =1kΩ IE I≅ C
3.3V
RE = 120KΩ
Circuit Diagram 3 - Circuit for monitoring the voltage changes across thermistor with temperature variations.NTC Thermistor is in its “Zero-Power”
mode.
V
10.3 Data Specifications
47ohm NTC Thermistor
* Family- Disc type
* Application- Temperature compensation in transistor circuits
* Resistance at 25C- 47ohm
* Material Constant Type- 2500( β in Kelvin)
* Maximum Wattage Rating, Pd(max.)-0.7Watts
* Maximum Temperature Rating -100C
* Dissipation Constant-6mW/C
* Typical Time Constant-75sec.
100 ohm NTC Thermistor
* Family- Disc type
* Application- Temperature compensation in transistor circuits
* Resistance at 25C- 100 ohm
* Material Constant Type- 3000( β in Kelvin)
* Maximum Wattage Rating, Pd(max.)-0.7Watts
* Maximum Temperature Rating -100C
* Dissipation Constant-6mW/C
* Typical Time Constant-75sec.
10k ohm NTC Thermistor
* Family- Glass Coated type
* Application- Fast Temperature Measurements
* Resistance at 25C- 10k ohm 20
* Material Constant Type- 3000 to 4000 ( β in Kelvin)
* Maximum Wattage Rating, Pd(max.)-0.05Watts
* Maximum Temperature Rating -200C
* Dissipation Constant-0.28mW/C
* Typical Time Constant-5sec.
BC107(NPN Transistor)
BEL Low Frequency Silicon Transistor
Application:-Driver stages of audio frequency amplifiers, signal processing
circuits, in T.V. and Low Power Low Speed Switching
Metal Encapsulation
Maximum collector Dissipation in free air at 25C, Pc=300 mW
Degrade in free air = 0.5C/mW
Absolute max. rating@25C:- BVCBO=50V, BVCEO=45V, BVEBO=6V,
IC=100mA
hFE@2mA=125 to 500
ICBO max.@VCB max.@25C=0.001A
VCE Saturation @10mA=0.25V
TON=98ns
TOFF=500ns
Outline (Packaging) = T018
Zener Diode CAZ3.3
VZ(nominal)-3.3volts
IZ = 20mA
IR = 5.0A(max.)
VR=1 volt
Typical temp. coeff. = -0.066%/C
Rd(typical)=22 Ω
Resistor
120kΩ, 1 kΩpot, 18 kΩ, 4.7 kΩ, 1 kΩ,12 kΩ,4.7 Ω,55 Ω, 22 Ω, 100 Ω, 47 Ω.
Type- Carbon film resistor
Reference Voltage
1.5V dry cell
Measuring Instrument
Digital Multimeter, Digital Thermometer
10.4 Tables of Experimental Observations
Readings of Thermistor Voltage Vs Temperature for 47 ohm NTC Thermistor when Thermistor is in Zero – Power Mode
Temp-erature
VoltageAcross Thermi-stor
Temp-erature
VoltageAcross Thermis-tor
Temp. VoltageAcross Thermi-stor
Temp. VoltageAcross Thermi-stor
Temp. VoltageAcross Thermi-stor
Temp. VoltageAcross Thermi-stor
(°C) (mV) (°C) (mV) (°C) (mV) (°C) (mV) (°C) (mV) (°C) (mV)
-6.8 36 8.2 35.5 35.6 34.0 60.5 33.3 76.0 33.1 91.5 33.2-6.0 35.9 10.3 35.4 37.2 34.0 61.0 33.3 76.5 33.1 92.0 33.1-5.6 35.8 11.8 35.5 39.9 33.9 61.5 33.2 77.0 33.1 92.5 33.1-5.4 35.9 14.0 35.4 40.4 33.9 62.0 33.2 77.5 33.1 93.0 33.1-5.3 35.8 15.0 35.3 41.7 33.8 62.5 33.1 78.0 33.2 93.5 33.1-5.0 36.0 16.0 35.1 42.6 33.8 63.0 33.1 78.5 33.2 94.0 33.1-4.8 36.1 16.9 35.0 44.2 33.7 63.5 33.1 79.0 33.1 94.5 33.2-4.6 36.3 17.0 34.9 45.5 33.7 64.0 33.1 79.5 33.2 95.0 33.1-4.4 36.2 18.0 34.8 46.0 33.6 64.5 33.1 80.0 33.2 95.5 33.1-4.3 36.2 18.7 34.7 46.5 33.5 65.0 33.1 80.5 33.2 96.0 33.1-4.2 36.2 19.2 34.7 47.5 33.5 65.5 33.2 81.0 33.2 96.5 33.1-3.6 35.7 20.0 34.6 48.0 33.5 66.0 33.1 82.5 33.2 97.0 33.1-3.2 35.7 21.4 34.7 49.0 33.6 66.5 33.2 83.0 33.2 97.5 33.0-3.0 35.7 23.1 35.1 50.0 33.5 67.5 33.2 83.5 33.2 98.0 33.1-2.0 35.7 24.6 35.2 51.3 33.5 68.0 33.2 84.0 33.2 98.5 33.1-2.0 35.6 25.3 35.1 52.1 33.5 68.5 33.2 84.5 33.2 99.0 33.1-1.3 35.5 26.3 35.3 52.5 33.5 69.0 33.2 85.0 33.2 99.1 33.1-1.0 35.5 26.8 34.7 53.0 33.5 70.0 33.2 85.5 33.2 99.2 33.0-0.9 35.5 27.0 34.6 54.0 33.5 70.5 33.2 86.0 33.2-0.3 35.5 27.6 34.3 55.0 33.4 71.0 33.2 86.5 33.20 35.4 28.2 34.4 55.7 33.3 71.5 33.2 87.0 33.20.4 35.5 28.4 34.5 56.0 33.3 72.0 33.2 87.5 33.20.5 35.5 28.5 34.4 56.5 33.3 72.5 33.2 88.0 33.21.5 35.3 28.8 34.6 57.0 33.3 73.0 33.1 88.5 33.13.0 35.4 28.9 34.5 57.5 33.3 73.5 33.1 89.0 33.23.5 35.4 30.6 34.1 58.0 33.3 74.0 33.1 89.5 33.13.8 35.5 32.3 34.1 59.0 33.3 74.5 33.1 90.0 33.13.9 35.4 34.2 34.0 59.5 33.3 75.0 33.1 90.5 33.17.6 35.5 34.5 34.0 60.0 33.3 75.5 33.1 91.0 33.1
TABLE-1
Reading of Thermistor Resistance Vs Temperature for 47ohm NTC Thermistor
Temp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance
( C) (ohm) ( C) (ohm) ( C) (ohm) ( C) (ohm)-3 117 22 54.4 48 25.3 74 14.2-2 113 23 53.2 49 25.4 75 13.1-1 110 24 52.1 50 24 76 12.40 107 25 50.6 51 22.9 78 11.91 97.5 26 48.9 52 23.4 79 11.72 97 27 47.2 53 22 80 10.93 96 28 46.8 54 21.9 81 11.44 94.3 29 45.4 55 20.2 82 115 89.8 30 43.6 56 20 83 9.96 89.1 30.7 41.9 57 19 84 197 88.5 31.5 42.4 58 18.7 85 10.38 86.5 34 37 59 18.1 86 109 84.2 35 35.1 60 17.3 87 9.4
10 81.6 36 34 61 17.4 88 10.211 79.2 37 32.8 62 16.3 89 9.212 76.3 38 31.3 63 16.3 90 9.513 74 39 30 64 14.9 91 9.714 71.4 40 29.1 65 15.8 92 9.715 69.7 41 27.6 66 16 93 8.916 66.7 42 26.9 67 13.9 94 8.317 64.4 43 26 68 14.4 95 9.518 62.5 44 25.9 69 14.9 96 9.419 60.6 45 25.8 70 14.620 59.2 47 24.3 71 13.7
TABLE-2
Readings of Resistance Vs Temperature of 100ohm NTC ThermistorTemp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance
( C) (ohm) ( C) (ohm) ( C) (ohm) ( C) (ohm)
-3 357 22 136.9 48 60.9 74 31.9-2 337 23 134.1 49 60.1 75 30.7-1 325 24 131.3 50 59.1 76 300 311 25 127 51 57 77 291 274 26 121.6 52 56 78 282 269 27 116.9 53 55.6 79 27.53 263 28 113 54 53.2 80 26.94 257.7 29 109 55 49.4 81 26.15 237.8 30 106.2 56 48.4 82 266 234.5 30.7 101.6 57 48 83 25.57 232.4 31.5 103.5 58 47.1 84 25.18 226.7 34 94.6 59 46.1 85 24.39 220.7 35 92.4 60 44.4 86 24.210 213.6 36 91.7 61 44.3 87 23.611 207 37 87.2 62 42.8 88 23.512 195 38 81.5 63 42.8 89 22.113 190.6 39 80.4 64 39.5 90 21.814 181.1 40 78.1 65 39.6 91 21.415 178 41 75.5 66 39 92 20.816 168.6 42 73.1 67 37.3 93 20.817 160.5 43 72 68 35.3 94 20.118 157.7 44 69 69 35.1 95 19.719 153.3 45 67.6 70 34.1 96 19.420 148.4 47 64.2 71 33.5
TABLE-8
Readings of Resistance Vs Temperature of 100ohm NTC Thermistor while applying Linearization Technique1
Temp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance
( C) (ohm) ( C) (ohm) ( C) (ohm) ( C) (ohm)17.8 139.2 33 87.9 49 56.3 68 3518 138.3 34 85.7 52 52.6 69 34.119 123.2 35.5 81 54 49.7 70 33.4
20 123.7 36 79.4 55 48.8 71 32.821 123 37.1 77.5 56 47.3 72 31.922 118.9 38 75.3 57 45.8 73 31.323 115.2 39 73.6 58 44.5 74 30.824 113 40 71.4 59.1 43.5 75 29.7
25.5 108.3 41 70.7 60 42.9 77 26.126 107.2 42 68.2 61 41.9 78 24.927 104 43 67 62 40.6 80 24.328 101 44 64.8 63 39.8 81 22.629 98.3 45 62.8 64 39.1 82 20.730 95 46 61.4 65 37.7 32 90.4 47 59.3 66 36.9 32 90.4 48 58.3 67 36.2
TABLE-9
Readings of Resistance Vs Temp. of 100ohm NTC Thermistor while applying linearization Technique2
Temp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance( C) (ohm) ( C) (ohm) ( C) (ohm) ( C) (ohm)11.5 113.1 40 92.4 64 76.9 84 68.317.9 112 42 89.8 65 76.6 86 67.9
20.3 108.2 46 87.9 66 75.7 88 6722.4 105.6 47 87.4 68 75.2 89 66.623.5 103.9 48 85.5 69 75 91 65.724.3 102.8 49 85.3 71 73.8 92.5 65.325.4 102.4 53.4 83.3 72 73.4 93.5 64.827.5 102.2 54 83 75.1 72.4 94.2 64.829.4 98.6 55 39.5 76 71.9 95 63.631 96.8 56.2 81.1 77 71.4 97 6334 95.5 58 80.3 78 70.8 98 62.635 94.9 60 79 79 70.4 99 62.537 92.8 61.2 78.4 80.3 69.8 99.2 61.239 93.1 62.2 78.3 82 69.3
TABLE-10
Readings of Output Voltage Vs Temperature of 100ohm NTC ThermistorTemp. Output Voltage Temp. Output Voltage Temp. Output Voltage Temp. Output Voltage
( C) (mV) ( C) (mV) ( C) (mV) ( C) (mV)1.5 426 30.3 803 55 1072 80 12572.5 423 31.3 820 56.1 1082 81.2 12635.2 421 33.1 836 59 1103 82.1 12686 468 34.1 853 59.5 1108 83 1273
6.8 474 36 879 60.1 1116 84.1 12817 475 37 885 61 1122 85 12849 510 38 896 64.8 1151 86 1289
10.7 527 39 910 65 1154 87 129311.6 530 40.2 924 66.5 1166 88 130113 540 41 936 67.7 1173 89 130414 559 43.1 944 68.3 1181 90 1311
15.1 6333 44 964 69 1186 91 1316
17.3 662 45 976 70 1194 92.1 132019.1 682 46 983 71 1200 93.1 132420.1 690 47 992 72.7 1210 94.5 133123 730 48 1001 73 1215 95 1334
24.2 737 49 1021 74 1220 96 133625 742 50 1028 75 1224 97 1339
26.2 752 51 1038 76.1 1233 98.1 134027 759 52 1046 77.1 1236 99 1342
28.1 767 53 1055 78 1244 29.1 774 54 1063 79 1250
TABLE-11
Readings of Output Voltage Vs Temperature of 100ohm NTC Thermistor while Linearization technique is applied
Temp.Output Voltage Temp.
Output Voltage Temp.
Output Voltage Temp.
Output Voltage
( C) (mV) ( C) (mV) ( C) (mV) ( C) (mV)14 729 43.5 815 64 890 82 941
14.4 720 44.1 820 65.4 893 84 94715 718 45.1 824 66 895 86.1 951
16.3 719 46 830 67.1 899 87 957s19.3 721 47 837 68 901 88 95818.5 727 49 839 69.2 904 89.1 96119 731 51.1 842 70 907 90 961
22.3 734 52 851 71 910 91 96424.1 736 53 854 72 913 92 96627 741 55.1 860 73.5 918 93 968
31.4 776 56 865 74.8 921 94.2 97234.7 788 58 873 76 924 95.2 975
37 789 60.1 876 77 936 96 97838.7 801 61 881 78 936 97.3 97940.8 806 62.2 886 79.3 937 98 97942 812 63 888 80 938 99 980
99.5 980
TABLE-12
Readings of Thermistor Voltage Vs Temperature of 10kohm NTC Thermistor in Zero-Power Mode
Temp. Thermistor Voltage Temp. Thermistor Voltage Temp. Thermistor Voltage( C) (mV) ( C) (mV) ( C) (mV)28 228 50 129.4 77 72.2
28.2 217.9 51 128 78 71.929 222 52 121.4 79 70.130 218.9 53 119 80 69.331 221.4 54 116 81 68.432 216.6 55 113 82 66.633 211.5 57 105 83 65.634 203.8 58 103.6 84 63.735 197 59 99 85 64.436 192.6 62 94.3 86 63.337 190.5 63 92.3 87 62.338 186.4 65 87.8 88 61.8
39 176.7 66 87 89 62.640 174.7 67 84.4 90 60.641 168.4 68 82 91 59.942 165.5 70 83.5 92 60.443 160.2 71 81.2 93 59.944 155.6 72 78.1 94 57.845 151 73 77.5 95 57.446 147 74 76.3 96 57.148 135.2 75 75.2 97 56.949 133.6 76 73.2 97.5 56.5
TABLE-13
Readings of Thermistor Voltage Vs Temperature of 10kohm NTC Thermistor in Zero-Power Mode when Linearization Technique 2 is applied
Temp.Thermistor
Voltage Temp.Thermistor
Voltage Temp.Thermistor
Voltage Temp.Thermistor
Voltage( C) (mV) ( C) (mV) ( C) (mV) ( C) (mV)-4.5 356 20 267.7 48 195.3 75.5 166.1-3 354 21 264.4 49 195.2 76.2 167-2 351.4 22 261.5 50 192.7 77 165.8
-1.2 347.2 23 258.5 51 192 79.5 164.4-0.6 344.5 24 256.2 52 189 80.3 163.4-0.5 343.5 25 253.9 53 189 81 163
0 341.8 26 250.8 54.1 183 82 162.71.2 337.4 27 247.5 55 186.2 84.3 159.32 334.2 28 245.5 56 184.3 86 160.23 331.9 29 242.3 57 181.6 87 1594 329.2 30 239.4 58 177.5 88 1595 326.2 31 236.9 59 179.8 89 157.9
6 323.3 32 234 60 181 90 158.17 321.4 33 232.3 61 178.4 91 156.88 318.5 34 223.2 62 176.4 92 156.29 315.1 35 221 64 173.8 93 155.1
10.4 310.3 36 219.5 65 176 94 154.511 308.3 37 212.2 66 173.4 95 154.312 305.1 38 207 67 170.8 96 154.413 298.7 39 211.5 68 173.2 97 153.914 293.3 40 210.2 69 172.5 98.1 153.715 290.1 42 204.8 70 170.6 98.8 153.416 285.6 43 201.4 71 168 99.3 153.417 281.9 44 201.3 72 167
18 276.6 45 200 73 167.719 271.6 46 200.5 74.3 166
TABLE-14
Readings of Resistance Vs Temperature of 10kohm NTC ThermistorTemp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance
( C) (kohm) ( C) (kohm) ( C) (kohm) ( C) (kohm)-19.2 67.8 0 22.52 27 9.64 64 2.709-19 67.3 1.7 22.5 28 9.62 65 2.64
-18.8 66.1 2 23.74 29 9.59 66 2.559-18.1 62.1 3 25.6 30 9.58 67 2.441-17.2 59.9 4 25.5 31 6.67 68 2.439-16.8 58.3 5 23.42 32 6.65 69 2.3-16.2 36.7 6 24.6 33 6.66 70 2.266-15.1 53.5 7 20.82 34 6.09 71 2.132-14.5 52 7.3 20.76 35 5.84 72 2.128-13.8 50 8 20.13 36 5.5 73 2.147-13.4 48.9 9 19.8 37 5.79 74 2.003-12.8 47.7 10 19.77 38 5.43 75 2.082-12.1 46.6 10.5 19.25 39 5.1 76 1.985
-11.5 46 12 17.87 40 4.95 77 1.838-11.2 45.7 13.3 16.57 41 4.37 78 1.807-10.4 45 13.5 16.42 42 4.56 79 1.735-9.1 39.07 14 16.24 43 4.46 80 1.674-8.4 37.72 14.3 15.88 44 4.46 81 1.56-7.3 35.66 15 15.62 46 4.97 82 1569-6.2 33.95 15.9 14.79 47 4.59 83 1.541-5.1 32.1 17 13.47 49 4.5 84 1.511-4.1 30.25 19 12.89 50 4.2 85 1.451-3.6 29.75 19.5 12.53 51 4.28 86 1.411-2 27.35 19.6 12.31 52 4.24 87 1.296
-1.5 26.59 20 12.15 53 3.88 88 1.374-1.1 26.43 21 11.84 54 3.79 89 1.319-0.9 26.14 21.5 11.6 55 3.6 90 1.279-0.8 26.05 22 11.54 56 3.409 91 1267-0.7 26.18 23 11.17 57 3.348 92 1.23-0.6 26.14 24 10.84 58 3.23 93 1.108-0.5 25.98 24.7 10.53 59 3.152 95 1.228-0.4 26.25 24.6 10.48 60 2.97 97 1.15-0.3 26.08 25.1 10.35 61 2.82 98 1.146-0.2 26 25.4 10.09 62 2.849 98.4 1.23-0.1 26 26 9.86 63 2.75 98.8 1.113
TABLE-15
Readings of Resistance Vs Temperature of 10kohm NTC Thermistor when Linearization Technique 1 is applied
Temp. Resistance Temp. Resistance Temp. Resistance Temp. Resistance ( C) (kohm) ( C) (kohm) ( C) (kohm) ( C) (kohm)
-18.1 9.77 9 5.1 38 4.07 75 1.603 -17.7 9.78 10 5.27 39 3.81 77 1.475 -17 9.64 11 5.24 40 3.68 78 1.459
-16.1 9.58 12.2 5.32 41 3.7 79 1.423 -15 9.48 13.2 5.16 42 3.54 80 1.416
-14.3 9.42 14 5.34 45 3.31 82 1.324 -13.4 9.36 15 5.26 47 3.175 83 1.295 -12.2 9.27 16 5.23 48 3.003 84 1.267 -11.3 9.21 17 5.11 49 3.983 85 1.25 -10.1 9.11 18 4.96 52 2.856 86 1.208 -9.1 9 19 4.97 54 2.69 87 1.197 -8.1 8.92 20 4.91 55 2.645 88 1.186 -7.1 8.84 21 4.92 56 2.529 89 1.124
-6.1 8.78 22.3 4.92 57 2.518 90 1.1 -5 8.73 23 4.9 58 2.4 91 1.078 -4 8.68 24 4.95 59 2.318 92 1.052 -3 8.64 25 4.81 60 2.318 93 1.047 -2 8.59 25.5 4.82 61 2.272 94 1.028 -1 8.86 26 4.79 62 2.181 95 1 0 8.75 27.4 4.83 64 2.07 96 0.976 1 8.64 29 4.72 66 1.971 97 0.55
3.5 8.29 30.3 4.51 67 1.914 98 0.37 3.9 8.26 31.4 4.8 70 1.784 99 0.32 5 7.42 32.3 4.83 71 1.737 100 0.915 6 7.28 32.7 4.81 72 1.72 7 7.1 35.8 4.26 73 1.685 8 6.93 37 4.14 74 1.609
TABLE-16
S
Readings of Output Voltage Vs Temperature of 10kohm NTC Thermistor
Temp. Output Voltage Temp.Output Voltage Temp.
Output Voltage Temp.
Output Voltage
( C) (Mv) ( C) (Mv) ( C) (Mv) ( C) (Mv)11.9 353 36 639 55.1 871 79 114112.2 354 37.1 633 56 884 80.1 114912.5 356 37.5 645 57 896 81 116614 358 38 682 58 906 82.1 117316 374 39 663 59.2 944 84 118017 396 40 685 61.8 968 85.1 119718 412 41.1 684 62 964 86.1 1198
19.5 412 42 688 63 970 87.1 121321 424 43.1 707 64.1 980 88.1 1218
22.1 459 44 724 65.1 1000 89.2 122023.3 453 45 735 67.3 1008 91 124125 476 46 758 68.1 1028 92 1247
26.1 502 47.1 775 69 1048 93 125727 500 48.1 793 70.1 1053 94 126129 532 49 814 72.1 1061 95.1 127330 573 50.2 813 74.1 1088 96.1 127731 574 51.6 829 75.2 1100 97.2 128632 568 52 831 76.2 1108 98 129033 582 53 867 77 1120 99 130235 617 54.5 865 78 1128 99.6 1304
TABLE-18
Readings of Output Voltage Vs Temperature of 10kohm NTC Thermistor when Linearization Technique is applied
Temp. Output Voltage Temp. Output Voltage Temp. Output Voltage( C) (mV) ( C) (mV) ( C) (mV)13.3 417 48 568 78.1 68217.2 432 49 572 79.3 68618.6 433 50 579 80.4 68619.2 448 51 580 81.1 69220 451 52 586 82.1 69222 452 53 588 83.1 69424 455 54 590 84.1 697
26.1 473 56 600 85.4 70227 473 57 608 87 703
29.1 477 58 613 89 70930 487 59 619 90 712
32.1 494 60 620 91 71634 500 62 624 92.2 72035 514 63.1 630 93.3 722
37.2 518 64 636 94 72238 520 65 639 95.1 72439 526 66.2 646 96.1 72540 529 67 646 97.2 72941 533 68 649 99.1 730
42.1 542 70.1 658 99.7 73143.1 549 72 659 100.3 73344.8 556 73.2 664 101 73346 562 75.1 670 47 568 77.1 677
TABLE-19
10.5 Graphs
11. References
1. http://www.microchip.com
2. www.maxim-ic.com
3. www.octsensors.com
4. www.hwalon.com
5. www.cantherm.com
6. http://www.epcos.com
7. http://www.engineeringtoolbox.com
8. Practical Semi-Conductor Data Manual, Vol.1 --------------------
Gyan C. Jain, B.P.B. Publications, Delhi, Madras, Hyderabad-- (pg.29, 47, 63)
9. Instrumentation For Engineering Measurements------------------James W. Dally, William F. Riley, Kenneth G.Mc Connell. John Wiley & Sons Inc., New York. ----------------Ch-2(pg.24-25), Ch-5(pg.124-158), Ch-6(pg.162-206), Ch-11(pg.412-466).
10. Measurement Systems Applications And Design-----------------
Earnest O. Doebelin, TMH Publication, New Delhi. --------------
Ch-3 (pp.40-103), Ch-8 (pp.677-791).
11. Introduction to Instrumentation And Control----------------------
Arun K Ghosh, PHI Pvt. Ltd., New Delhi. ----Ch-9(pp.142-163)
12. An Integrated Course in Electronics Engineering -----------------
J. B. Gupta, S.K.Kataria & Sons, Delhi Edition 2010-11 (pg.564)
